An electrical connector includes an insulative housing having a base and a tongue, an upper and lower rows of contacts mounted in the insulative housing and exposed upon the tongue and a pair of grounding pieces separated from each other and retained in the insulative housing between the two rows of contacts. Each grounding piece includes a securing portion disposed in the mating tongue and defines an abutment exposed upon corresponding side face of the mating tongue. The pair of grounding pieces are far away from corresponding power contacts along the transverse direction thereby resulting that the grounding pieces are wholly offset from the power contacts in the vertical direction so as to avoid the power contacts from electrical sparkle.